[OpenMP][OMPT] Add two missing nullpointer checks in ompt-multiplex.h

[protze.joachim]

Summary

In the functions ompt_multiplex_get_own_ompt_data
and ompt_multiplex_get_client_ompt_data in addition to
data being NULL, also the void pointer field "ptr" of
"data" could be NULL, leading to a subsequent
segfault.
This patch add the corresponding checks.

Patch prepared by Semih Burak

[jdoerfert]

LG

openmp/tools/multiplex/ompt-multiplex.h

 
 static void ompt_multiplex_free_data_pair(ompt_data_t *data_pointer) {
   free((*data_pointer).ptr);
 }
 
 static ompt_data_t *ompt_multiplex_get_own_ompt_data(ompt_data_t *data) {
   if (!data)
     return NULL;
+  if (!data->ptr)
+    return NULL;
   ompt_multiplex_data_pair_t *data_pair =
       (ompt_multiplex_data_pair_t *)data->ptr;
   return &(data_pair->own_data);
 }
 
 static ompt_data_t *ompt_multiplex_get_client_ompt_data(ompt_data_t *data) {
   if (!data)
     return NULL;
+  if (!data->ptr)
+    return NULL;
   ompt_multiplex_data_pair_t *data_pair =
       (ompt_multiplex_data_pair_t *)data->ptr;
   return &(data_pair->client_data);
 }
 #endif //! defined(OMPT_MULTIPLEX_CUSTOM_GET_CLIENT_THREAD_DATA) ||
        //! !defined(OMPT_MULTIPLEX_CUSTOM_GET_CLIENT_PARALLEL_DATA) ||
        //! !defined(OMPT_MULTIPLEX_CUSTOM_GET_CLIENT_TASK_DATA) ||
        //! !defined(OMPT_MULTIPLEX_CUSTOM_GET_CLIENT_TARGET_DATA)